Liquid Discharge Head Wiring Layout to Keep Adhesive Off Terminals
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Solution Overview
Problem
Adhesive adherence to connection terminals in discharge units of liquid discharge heads, such as inkjet printers, inhibits bonding and reduces electric reliability.
Innovation Solution
Incorporating a protruding portion on the electric wiring substrate that overlaps the connection terminal and is positioned to prevent adhesive adhesion, combined with a surface modification process to reduce contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to bond the electric wiring substrate to the support member, then bonding strength is improved, but adhesive adheres to the connection terminal and inhibits wire bonding
Solution Approach 1:
The electric wiring substrate is divided into functional zones: a bonding area where adhesive is applied to the support member, and a terminal area where the connection terminal protrudes to prevent adhesive adhesion. This spatial segmentation ensures that adhesive bonding and electrical connection functions are separated, allowing strong bonding without compromising wire bonding capability
Solution Approach 2:
The connection terminal is designed to protrude from the electric wiring substrate before the adhesive bonding process. This preliminary configuration of the terminal protrusion structure prevents adhesive from reaching the terminal during the bonding process, eliminating the need for post-bonding cleaning or rework
2Area of stationary object
If the connection terminal is positioned close to the bonding area for compact design, then device size is reduced, but adhesive adheres to the terminal and prevents wire bonding
Solution Approach 1:
The connection terminal is extended in the vertical dimension (protruding from the substrate surface) rather than only in the horizontal plane. This dimensional change allows the terminal to overlap with the bonding area in the plan view while maintaining physical separation in the vertical direction, preventing adhesive adhesion while preserving compact footprint
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents adhesive adhesion to connection terminals, ensuring stable bonding and enhancing electric reliability of the discharge unit.
Implementation Method 1
the electric wiring substrate further has a protruding portion which protrudes from the end surface of the electric wiring substrate toward the element substrate, the protruding portion being provided by having an interval with respect to the support surface
Implementation Method 2
a surface modification process which removes contamination on the terminal of the electric wiring substrate
Implementation Method 3
an adhesive which bonds the electric wiring substrate and the support member
Data Source
AI summary
A discharge unit includes an element substrate having a discharge port which discharges a liquid, an electric wiring substrate having an end surface opposed to the element substrate and a terminal electrically connected to the element substrate, a support member which supports the element substrate and the electric wiring substrate with a support surface, and an adhesive which bonds the electric wiring substrate and the support member. The electric wiring substrate further has a protruding portion which is provided with an interval with respect to the support surface and protrudes from the end surface of the electric wiring substrate toward the element substrate, and the protruding portion is provided at a position overlapping the terminal in a direction parallel to the support surface and orthogonal to a protruding direction of the protruding portion.